Process for producing fat composition

ABSTRACT

Disclosed is a method of producing a fat and oil composition comprising the steps of melting a fat and oil, or emulsion comprising fat and oil, and crystallizing the above-mentioned fat and oil by cooling to produce a fat and oil composition in paste form or plastic form. The molten fat and oil, or emulsion comprising fat and oil, is pressurized under force at a pressure of 10 to 150 MPa during the above-mentioned crystallization in the production of fat and oil compositions such as fat and oil processed foods, etc. As a result the crystallization speed of the fat and oil is markedly increased and post-crystallization can be prevented. Thus, improvement in quality of the fat and oil processed food and improved efficiency of the production process in terms of time and energy is achieved.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention pertains to a method of producing a fat and oilcomposition in paste form or plastic form by cooling molten fat and oilor an emulsion comprising fat and oil, etc., in order to crystallize thefat and oil, and in further detail, to a method of producing a fat andoil with which it becomes possible to curtail and make efficient theproduction process when fat and oil processed foods, such as margarineor shortening, are produced.

2. Description of the Related Art

The process of producing fat and oil processed foods such as margarine,shortening, etc., usually involves crystallization, that is, theformation of crystals, of the fat and oil by cooling and kneading amolten fat and oil or emulsion to obtain a product in paste form orplastic form. Closed continuous-type scraped-surface heat exchangers andopen chillers are given as the cooling and kneading device that isgenerally used at this time. Examples of the above-mentioned closedcontinuous-type scraped-surface heat exchangers are the Kombinator(Schroeder & Co., Germany), Votator (Cherry-Burrell Votator Division,USA)), Perfector (Gersternberg & Agger A/S, Denmark)), Chemetator (CrownChemtech, Ltd., UK)), etc., and these are generally referred to as Aunits. Moreover, the Diacooler (Gersternberg & Agger A/S, Denmark)) isan example of the above-mentioned open chiller.

The above-mentioned closed continuous-type scraped-surface heatexchanger (A unit) uniformly kneads while scraping the surface ascooling and crystallization occur from around the molten composition,which has been introduced by a pump and is passing through the tubularheat exchanger unit. Nevertheless, thorough crystallization cannot beaccomplished within the short cooling time of this type of cooling andkneading device. As a result, crystallization actually graduallyproceeds once the product has been produced. However, this phenomenon ofgradual crystallization following production is referred to aspost-crystallization, and the crystals that are produced at this timegenerally become the cause of a marked reduction in the variouscommercial properties of fat and oil products with large crystalformation readily occurring, the product having a coarse texture, theproduct readily cracking, poor spreading performance, that is,spreadability, poor whipping performance, etc.

On the other hand, by means of the above-mentioned open chiller, forinstance, the fat and oil composition is applied directly to the drum ofthe Diacooler and rapidly cooled and solidified and the fat and oil thatis scraped off in the form of a thin piece is then kneaded under reducedpressure in the Complector (Gersternberg & Agger A/S, Denmark), etc., toobtain the product. Nevertheless, this type of cooling and kneadingdevice is an open device and therefore, there are problems with hygiene.Moreover, the fat and oil that has been rapidly cooled and solidifiedmust be kept in the hopper for several hours or longer for maturationand there is therefore a need to curtail the production time.

There are problems with producing fat and oil processed foods aspreviously described in that it takes a long time to thoroughlyprecipitate the crystals when the fat and oil is crystallized and ifcrystallization is performed in a short amount of time, the quality ofthe product will deteriorate due to post-crystallization. Various testshave been thus far performed that have involved, for instance, changingthe shape or clearance of the heat exchanger unit, using- a series ofseveral heat exchanger units, and changing the cooling temperature inorder to improve cooling efficiency of closed continuous-typescraped-surface heat exchangers in an attempt to solve theabove-mentioned problems. Moreover, attempts have also been made topromote crystallization by placing a holding unit between each coolingunit. Nevertheless, thus far it has not be possible to completelyprevent post-crystallization and it usually is impossible to obtain apuff pastry or a sheet shape margarine product, wherein quality isparticularly a problem, by using cylindrical units called resting tubesafter cooling and kneading, or by gradually kneading as the fat and oilcomposition is being passed through a resting tube with a varyingdiameter as needed, because crystallization is not completed up to thepoint where post-crystallization no longer has a detrimental effect.Efficiency deteriorates over time and a considerable amount of labor isrequired in order to treat the fat and oil composition remaining in theresting tube when the lines are washed after production is completed,etc., leading to poor yield of the product. On the other hand, problemsremain when an open chiller is used in that in addition to theabove-mentioned hygiene problem, production takes a considerable amountof time because a maturation process is needed. A sufficient air contentis not realized by conventional production processes, particularly withprocessed fat and oil products for butter cream, due to the effects ofpost-crystallization of the fat and oil crystals as previouslydescribed, and the fat and oil composition must be kept for several tenhours at a temperature that is 2 to 5° C. lower than the melting pointof the fat and oil in order to impart a sufficient air content. Amaturation process called “tempering” in Japan is generally necessary,and this leads to a large loss in terms of both energy and time.

Thus, although various research and production efforts have beenpreviously made in order to eliminate the detrimental effects ofpost-crystallization on the various uses of fat and oil processed foods,a solution that is sufficient for realizing efficient crystallization offats and oils has yet to be found and development of a technology withwhich crystallization can be completed in a short amount of time duringproduction of fat and oil processed foods in order to eliminate thedetrimental effects of post-crystallization is eagerly awaited.

SUMMARY OF THE INVENTION

The above-mentioned various problem points are problems that cannot beavoided simply by crystallization by cooling during the production offat and oil processed foods. Therefore, the inventors performed intensestudies based on the idea that each of the above-mentioned problems canbe solved not simply by relying on cooling only for crystallization, butby concomitantly using other methods in order to completecrystallization of the fat and oil composition in a short amount oftime, and that actually, it is probably possible to curtail thecrystallization time by applying pressure during crystallization, and asa result, they completed the present invention upon discovering that thecrystallization starting temperature can be increased and therefore, thecrystallization completion time can be markedly curtailed, by forceapplication of pressure by some type of method during cooling andcrystallization.

That is, the present invention is a method of producing a fat and oilcomposition, comprising the steps of melting fat and oil or emulsioncomprising fat and oil and cooling this to crystallize theabove-mentioned fat and oil and produce a fat and oil composition inpaste form or plastic form, with pressure being applied by force to theabove-mentioned molten fat and oil or emulsion comprising fat and oilduring the above-mentioned crystallization.

By means of a preferred embodiment of the method of producing a fat andoil composition of the present invention, pressure is first appliedafter the above-mentioned fat and oil or emulsion comprising fat and oilhas been pre-cooled to such an extent that crystals of theabove-mentioned fat and oil do not precipitate. Moreover, by means of apreferred embodiment, pressure is within a range of 10 to 150 MPa and bymeans of a preferred embodiment, pressurization time is 1 to 60 minutes.Moreover, it is preferred that the fat and oil be kneaded simultaneouslywith crystallization of the fat and oil or after crystallization of thefat and oil by the method of the present invention. It is furtherpreferred that the above-mentioned emulsion be a W/O emulsion. Theabove-mentioned method of producing a fat and oil composition of thepresent invention is particularly useful for the production of fat andoil processed foods that use edible fats and oils or emulsionscontaining fats and oils as their starting material.

The fat and oil used in the present invention is an edible fat and oilthat is normally used in edible fat and oil food products. Natural oils,such as animal oils, vegetable oils, milk fat, etc., their hardenedoils, fractionated oils, interesterificated oils, randominteresterificated oil, etc., alone, or their mixed oils are used. Theyare used as a fat and oil only or as a W/O emulsion that has beenemulsified with water. There are no problems with adding flavoringcomponents, fragrance, nutrient component, emulsifiers, gelling agents,antioxidants, etc., that are normally added to fat and oil processedfoods to the above-mentioned fat and oil or its emulsion.

One example of an actual method of producing a fat and oil compositionby the method of the present invention will be given. First, theabove-mentioned edible fat and oil or its emulsion is melted to atemperature at which the above-mentioned fat and oil will completelymelt (usually 65° C.). Next, the above-mentioned molten fat and oil oremulsion is introduced to inside a hydrostatic vessel and pressurized.It is possible to simultaneously cool while pressurization is beingperformed by cooling the hydrostatic medium in the hydrostatic vessel.The pressure device of the above-mentioned hydrostatic vessel can be asystem such as a piston system or hydraulic system, but it should not bea pneumatic system in terms of cooling efficiency, pressurizationcapability, and safety. Moreover, pressurization can be performed by thebatch system or the continuous system. Optimum pressure, pressurizationtime, and temperature of the hydrostatic medium differ with thecomposition of the starting edible fat and oil that is used, amount ofsolid fat, melting point, etc., and cannot unconditionally specified,but it is usually preferred that treatment be performed within a rangeof pressure of 10 to 150 MPa, pressurization time of 1 to 60 minutes,and hydrostatic medium temperature of −30 to 15° C. It is often the casethat if the above-mentioned pressurization pressure is less than 10 MPa,crystallization by pressurization will not be sufficiently promoted andwill have little effect, and a pressure higher than what is necessary isundesirable, both in terms of economics and safety. The pressurizationtime is determined giving equal consideration to pressure, temperature,the fat and oil composition, etc., but if it is less than 1 minute,crystallization will usually be insufficient in most cases. There is nodeterioration in quality of the fat and oil properties, etc., ifpressurization is continued after crystallization has been completed,but there is little further effect and actually, it is not necessary tocontinue pressurization for more than 60 minutes. If the temperature ofthe above-mentioned hydrostatic medium is higher than 15° C., coolingspeed will be delayed and the crystallization time will be long, evenwith the effects of pressurization, and it will be difficult to obtain alarge improvement. On the other hand, although the cooling speed is fastwhen the temperature of the hydrostatic medium is under −30° C.,pressurization will have little effect in terms of promotingcrystallization, and this is also undesirable in terms of economics. Inaddition, although sufficient results are seen with just onepressurization treatment, there is further improvement when the sametreatment is repeated as necessary when crystallization is insufficient,etc.

Furthermore, the term crystallization in the present invention means theformation of crystals whereby the molten fat and oil changes to a solidfat. In addition, the term completion of crystallization means the statewhere the component that should crystallize at that temperature hascompletely crystallized. Furthermore the term “kneading” in the presentinvention means mechanical agitation and kneading of the fat and oilcomposition.

In addition, by means of the present invention, pressurization can beperformed simultaneously with cooling, but it is also possible to startpressurization after pre-cooling the edible fat and oil or its emulsionwith a conventional cooling device to such an extent that the crystalshave not precipitated. Better properties as an edible processed fat andoil are obtained in this case because since the fat and oil has beenpre-cooled, the crystallization starting temperature rises withpressurization and therefore, crystallization will occur in one breathat the time of pressurization and as a result, the crystals that areobtained will be fine crystals. Furthermore, results such as curtailmentof the processing time, curtailment of the crystallization time, etc.,will also be obtained.

It is preferred that a fat and oil composition such as margarine,shortening, etc., be continuously produced by, for instance,simultaneously kneading with crystallization, in addition to cooling andcrystallizing by pressurization, the fat and oil composition or emulsionusing a cooling and kneading device such as an extruder with apressure-resistant structure, or a conventional closed, continuous-typescraped-surface heat exchanger device (A unit) that has apressure-resistant structure as needed, with the gears being adjustedusing a reverse screw, or pressure being adjusted with a gear pump, bytubing diameter being changed, etc., when the above-mentioned extruderis used, or pressure being adjusted with the gear pump or by tubingdiameter being changed, etc., when a cooling and kneading device such asthe above-mentioned closed continuous-type scraped-surface heatexchanger device (A unit) is used, as a method of industrially producingthe fat and oil composition, such as an edible processed fat and oil, ofthe present invention. The fat and oil composition, such as margarine,shortening, etc., can also be produced by, for instance, continuouslyfeeding pre-melted fat and oil or emulsion to a pressure-resistantvessel with a cooling means and pressurization means, such as apressure-resistant vessel equipped with a cooling means and apressurization piston, simultaneously performing cooling by theabove-mentioned cooling means and pressurization by the pressurizationpiston to crystallize the fat and oil, and once crystallization of thefat and oil is completed, kneading the product with a kneading unit,such as a screw kneader, etc., as another method.

For instance, FIG. 1 shows the production process whereby extruder 1,cooling and kneading device (A unit) 2, and kneading device (X unit) 3are joined by piping 4. Above-mentioned extruder 1 has screw 5 in thefront half and reverse screw 6 in the back half and cooling jacket 7 iswhere said reverse screw 6 is placed. By means of producing the fat andoil composition by the process shown in FIG. 1, when fat and oilstarting material, such as edible fat and oil or its emulsion, etc.,that has been pre-melted is fed through tubing 4 to extruder 1, the fatand oil starting material that has been fed is sent forward by screw 5,but because screw 6 at the back half of extruder 1 is a reverse screw,the fat and oil starting material is cooled by cooling jacket 7 aspressure is simultaneously applied by force to the fat and oil startingmaterial and as a result, crystallization of the fat and oil takesplace. Moreover, kneading by reverse screw 6 is simultaneously performedwith this crystallization. Thus, the majority of the molten fat and oilstarting material crystallizes inside above-mentioned extruder 1. Thenthe above-mentioned fat and oil that has been crystallized is sent to Aunit 2 and cooled further to complete crystallization. Furthermore, thefat and oil is pressurized by force in this A unit 2. Then it is sent toX unit 3 and further kneaded to obtain the final product. As previouslyexplained, by means of the process shown in FIG. 1, crystallization isperformed mainly by extruder 1 and A unit 2 is an auxiliary unit wherepressurization under force is not performed and therefore, a cooling andkneading device such as a conventional closed continuous-typescraped-surface heat exchanger device, etc., can be used as is for Aunit 2. Moreover, any type of structure can be used for above-mentionedX unit 3 as long as the crystallized fat and oil composition can bekneaded.

Next, FIG. 2 shows the production process whereby several cooling andkneading devices (A1 unit through A3 unit) 11 through 13 and kneadingdevice (B unit) 14 are connected by tubing 17 and gear pumps 15 and 16for feeding the fat and oil are placed between the units. By means ofproducing the fat and oil composition by the process in this FIG. 2, thefat and oil starting material, such as the pre-melted edible fat and oilor its emulsion, etc., is first fed to A1 unit 11 and then pre-cooled tosuch an extent that crystallization of the fat and oil does not occurhere. During this pre-cooling, pressurization is not performed underforce. Then the fat and oil is fed in succession to A1 unit 12 and A3unit 13 by gear pump 15 and here it is cooled further. The fat and oilis crystallized at this time by pressurization under force by adjustinggear pumps 15 and 16. Then the fat and oil is sent to B unit 14 andkneaded to obtain the product. Since pressurization under force is notperformed by above-mentioned A1 unit 11 in the process shown in FIG. 3,a conventional cooling and kneading device, such as a closedcontinuous-type scraped-surface heat exchanger device, etc., can be usedas is for A1 unit 11. On the other hand, since pressurization underforce by gear pumps 15 and 16 is performed in A2 unit 12 and A3 unit 13,it is necessary to use a cooling and kneading device with apressure-resistant design. Furthermore, if cooling and crystallizationby above-mentioned cooling and kneading devices (A1 through A3) 11through 13 is insufficient, the number of cooling devices can beincreased further to an A4 unit and so forth. In addition, any type ofstructure can be used for kneading device (B unit) 14 as long as thecrystallized fat and oil composition can be kneaded. For instance, aconventional kneading device called a pin machine can be used.

Furthermore, FIG. 3 shows the production process whereby kneading andshaping unit 25, such as a screw extruder, etc., is connected byextruder 24 to a plurality of crystallization units 21 through 23consisting of pressure-resistant vessels equipped with cooling means(not illustrated) and piston 26 for pressurization. Above-mentionedextruder 24 can also be omitted. By means of producing a fat and oilcomposition by the process shown in FIG. 3, the molten fat and oilstarting material, such as edible fat and oil or emulsion, etc., is fedto crystallization units 21 through 23 and pressurized under force bypiston 26 as it is being cooled and crystallized. Then it is sent tokneading and forming unit 25 by screw 27 of extruder 24 and here it iskneaded to obtain t he product. There are no restrictions to the numberof above-mentioned crystallization units 21 through 23, and as shown bythe broken curve in the figure, the crystallized fat and oil can be sentdirectly from crystallization units 21 through 23 to kneading andforming unit 25 by piping, etc., or a gear pump for feeding the fat andoil can be placed somewhere in the tubing, without installingabove-mentioned extruder 24.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a process explanatory drawing of one example of the industrialproduction process of the method of producing fat and oil composition ofthe present invention.

FIG. 2 is a process explanatory drawing showing another example of theindustrial production process of the method of producing fat and oilcomposition of the present invention.

FIG. 3 is a process explanatory drawing showing yet another example ofthe industrial production process of the method of producing fat and oilcomposition of the present invention.

FIG. 4 is a graph showing the creaming curve of the fat and oilcompositions of Example 1 and Comparative Example 1.

FIG. 5 is a graph showing the cooling curve of each mixed oil undervarious pressurization conditions of Example 2 (samples No. 21 through24) and Comparative Example 2 (sample No. 33).

FIG. 6 is a graph showing the cooling curve of each cocoa butter ofExample 3 (samples No. 25 through 28) and Comparative Example 3 (sampleNo. 34).

FIG. 7 is a graph showing the cooling curve under various pressureconditions of each pure palm oil of Example 4 (samples No. 29 through32) and Comparative Example 4 (sample No. 35).

FIG. 8 is a graph showing the cooling curve of mixed oil underconditions of pressurization to 50 MPa after pre-cooling (Example 7).

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will now be explained in further detail by givingexamples and comparative examples, but the present invention is in noway limited to these examples. Furthermore, unless otherwise noted, the“%” in the following entry is always “wt %.”

(Example 1)

A mixed oil of 50% hard palm oil, 20% lard, and 30% pure corn oil(melting point of 34.1° C.; solid fat content at 5° C. by standardmethods=75.2%) was melted at 65° C. and then introduced to a hydrostaticvessel (capacity of approximately 50 cc). Then samples that had beencrystallized in a hydrostatic medium (50% ethanol) that had been cooledto 5° C. by pressurization to 10 MPa, 50 MPa, 100 MPa and 150 MPa at apressurization time of 10 minutes, 20 minutes, 40 minutes and 60minutes, respectively, were prepared and the solid fat content of thesamples (No. 1 through 16) immediately after this treatment wasdetermined. Furthermore, the solid fat content was determined using theSolid Fat Content Analyzer made by Praxis Corporation (USA) (Praxis SFCAnalyzer Model SFC-900A/486) with olive oil as the control sample.

(Comparative Example 1)

Mixed oil of the same ingredients as in Example 1 was melted at 65° C.and introduced to the same hydrostatic vessel. Then samples that hadbeen crystallized by being kept in the hydrostatic medium (50% ethanol)cooled to 5° C. without pressurization for 10 minutes, 20 minutes, 40minutes, and 60 minutes were prepared and the solid fat content of thesamples (No. 17 through 20) immediately after treatment was determinedby the same method as in Example 1.

The results of determining the solid fat content and percentagecrystallization of each sample obtained in Example 1 and ComparativeExample 1 are shown in Table 1. Furthermore, the crystallizationpercentage here is the he solid weight content at 5° C. by standard dmethod of determining solid fat content of hod CD-81) of the mixed oilthat was used.

TABLE 1 Example 1 (samples No. 1 ˜ 16), Comparative Example 1 (sampleNo. 17 ˜ 20) Sample Pressure Time Solid fat Crystallization No. (MPa)(minutes) content (%) percentage (%) Example 1 1 10 10 57.5 76.5 2 10 2067.5 89.8 3 10 40 73.8 98.1 4 10 60 74.6 99.2 5 50 10 61.8 82.2 6 50 2069.8 92.8 7 50 40 74.6 99.2 8 50 60 74.9 99.6 9 100 10 65.1 86.6 10 10020 71.8 95.5 11 100 40 74.5 99.1 12 100 60 74.9 99.6 13 150 10 66.3 88.214 150 20 72.5 96.4 15 150 40 74.8 99.5 Compar- 17 Normal 10 26.3 35.0ative pressure Example 1 18 Normal 20 54.1 71.9 pressure 19 Normal 4064.1 85.2 pressure 20 Normal 60 66.3 88.2 pressure

As is clear from the results in Table 1, by performing crystallizationin accordance with the present invention by pressurization at a pressureof 10 MPa or higher, crystallization of the fat and oil is markedlypromoted and when compared to the case where crystallization isperformed at normal pressure, crystallization is completed within ashort amount of time. Moreover, any further crystallization-promotingactivity gradually becomes smaller at a high pressure of 50 MPa orhigher and it appears that there is almost no effect when pressure isfurther increased to above 150 MPa.

Moreover, of the samples obtained in Example 1, 300 g each of sample(No. 6) that had been treated at a pressure of 50 MPa for apressurization time of 20 minutes and of sample No. 18 obtained inComparative Example 1 that had been treated for 20 minutes withoutperforming pressurization were kept overnight in a refrigerator (5° C.)and then temperature was brought to 25° C. for a 3-hour period andwhipping tests were performed at 25° C. with a Hobart mixer using a wirewhipper. Air content was compared by the overrun (%). The term overrunused here is the number represented by (A−x)/x×100 (A: capacity of scalepan×specific gravity of sample, x=sample weight). The results are shownin FIG. 4. Sample No. 18 (Comparative Example 1) that had not beenpressurized began to become flat in 10 minutes and thereafter gave offgas, while sample No. 6 (Example 1) that had been pressurized at 50 MPacontinued to show an increase in its overrun value for 20 minuteswithout becoming flat.

Furthermore, each physical property of texture, gloss, firmness, andspreadability (ease of spreading) when sample No. 6 (treatment pressureof 50 MPa and pressurization time of 20 minutes) that was obtained inExample 1 and sample No. 18 (treated for 20 minutes without beingpressurized) obtained in Comparative Example 1 as previously describedwere stored in a refrigerator (5° C.) overnight and then brought to 25°C. for a 3-hour-period were compared by organoleptic tests by a10-member panel at 25° C. The results are shown in Table 2.

TABLE 2 Examples 1 (Sample No. 6), Comparative example 1 (sample No. 18)Pressure (MPa) Texture Gloss Firmness Spreadability Example 1 50 4.2 3.84.6 3.6 Comparative Normal 2.6 2.3 2.1 1.8 Example 2 pressure Theratings in the table show the average rating out of a possible of 5points from the 10-member panel.

As is clear from Table 2, the evaluation of texture, gloss, firmness andspreadability (ease of spreading) of sample No. 6 (Example 1) that hadbeen pressurized were all superior to sample No. 18 (ComparativeExample 1) that had not been pressurized within a range of significantdifference.

(Examples 2 through 4)

A mixed oil with the same composition as in Example 1 was used as thesample. This sample was melted at 65° C. and then introduced to the sametype of hydrostatic vessel. Then temperature changes in the center ofsamples (No. 21 through 24) were monitored with a sensor as the sampleswere pressurized in a hydrostatic medium (50% ethanol) that had beencooled to 5° C. to 10 MPa, 50 MPa, 100 MPa and 150 MPa for 20 minutes(Example 2). Moreover, the same treatment was performed with theexception that the mixed oil was changed to cocoa butter (Example 3,Samples No. 25 through 28) and pure palm oil (Example 4, samples No. 29through 32).

(Comparative Examples 2 through 4)

Other than the fact that there was no pressurization, the same fats andoils were treated under the same treatment conditions as in Examples 2through 4 and the changes in temperature in the center of the samples(No. 33 through 35) were monitored with a sensor.

The results of Examples 2 through 4 and Comparative Examples 2 through 4(cooling curve) are shown in FIGS. 5 through 7. There is a reduction intemperature with time and a peak or inflection point is seen at acertain temperature in FIGS. 5 through 7. This appears to be due to aphase change, that is, the heat of crystallization as a result ofcrystallization of the sample. As is clear from FIGS. 5 and 7, theinflection point of temperature, that is, the crystallization startingtemperature, rises with an increase in pressure and crystallization offats and oils comprising various solid fats is promoted. Moreover,although the purified palm oil in FIG. 7 did not thoroughly crystallizein 20 minutes at normal pressure and remained fluid, crystallizationproceeded when pressurized by force at 10 MPa or more and fat and oilcrystals with shape retention were obtained. Therefore, it is clear thatthe crystallization-promoting activity of pressurization is effective.

(Example 5)

Using a W/O emulsion consisting of 80% mixed oil of 50% hard palm oil,20% lard, and 30% pure corn oil (melting point of 34.1° C.), 0.2%glycerin monofatty acid ester (Emaruji MS, Riken Vitamin Co., Ltd.),0.2% lecithin, and 19.6% water, margarine was produced with the systemshown in FIG. 2 under the various operating conditions in Table 3 whilecontrolling pressure of A2 unit 12 and A3 unit 13 to 30 MPa with gearpumps 15 and 16. The margarine that was obtained was stored in arefrigerator (5° C.) overnight and then each fat and oil property oftexture, gloss, firmness, and spreadability (ease of spreading) wereevaluated by organoleptic tests by a 10-member panel using the sameevaluation method as in Table 2.

(Comparative Example 5)

Using the same emulsion as in Example 5, margarine was produced with thesame system under the various operating conditions in Table 3 inaccordance with conventional methods without any particular adjustmentof pressure by the gear pumps. As in Example 5, the margarine that wasobtained was stored overnight in a refrigerator (5° C.) and then thevarious fat and oil properties of texture, gloss, firmness, andspreadability (ease of spreading) were evaluated by a 10-member panelwith the same evaluation method as in Table 2.

TABLE 3 Operating conditions A1 unit A1 unit A2 unit A3 unit B unitinlet outlet outlet outlet outlet A2 unit tempera- tempera- tempera-tempera- tempera- outlet ture ture ture ture ture pressure Example 5 58°C. 28° C. 30° C. 20° C. 21° C.  30 MPa Comparative 59° C. 29° C. 20° C.17° C. 24° C. 2.5 MPa Example 5

The results of organoleptic evaluation of above-mentioned Example 5 andComparative Example 5 are shown in Table 4.

TABLE 4 Examples 5, Comparative example 5 Pressure (MPa) Texture GlossFirmness Spreadability Example 5 30 4.6 4.4 4.5 4.5 Comparative NormalExample 5 pressure 3.5 3.3 3.4 2.8 The ratings in the table show theaverage rating out of a possible of 5 points from the 10-member panel.

(Example 6)

Margarine was produced by the system shown in FIG. 3 using the sameemulsion as in Example 5 by going through a kneading process aftercrystallization for 30 minutes at a pressure of 30 MPa and a coolingmedium temperature of −15° C. in crystallization units 21 through 23.After storing the margarine that was obtained in a refrigerator (5° C.)overnight, each fat and oil property of texture, gloss, firmness, andspreadability (ease of spreading) was evaluated by organoleptic tests bya 10-member panel using the same evaluation methods as in Table 2.

Comparative Example 6

Using the same emulsion as in Example 6, margarine was produced with thesame system as in Example 6 without any particular adjustment ofpressure by the gear pumps. The margarine that was obtained was storedovernight in a refrigerator (5° C.) and then the various fat and oilproperties of texture, gloss, firmness, and spreadability (ease ofspreading) were evaluated by a 10-member panel using the same evaluationmethod as in Table 2.

The results of the organoleptic tests in above-mentioned Example 6 andComparative Example 6 are shown in Table 5.

TABLE 5 Examples 6, Comparative example 6 Pressure (MPa) Texture GlossFirmness Spreadability Example 6 30 4.2 4.1 4.5 4.1 Comparative NormalExample 6 pressure 2.8 2.9 3.0 2.5 The ratings in the table show theaverage rating out of a possible of 5 points from the 10-member panel.

As is clear from Tables 4 and 5, the margarines of Examples 5 and 6 thatwere produced by crystallization accompanied by pressurization hadexcellent ratings in terms of texture, gloss, firmness, andspreadability (ease of spreading) when compared to the margarines inComparative Examples 5 and 6 that were produced by crystallizationwithout pressurization. Moreover, although in Example 5 the margarinewas cooled by the A2 unit, the A2 outlet temperature rose somewhat underthe operating conditions in Table 3. However, this was because heat ofcrystallization was generated and this rise in outlet temperaturetherefore indicates that crystallization occurs all at once in the A2unit.

(Example 7)

A mixed oil with the same ingredients as in Example 1 was melted at 65°C. and introduced to the same hydrostatic vessel. Then it was cooled ina hydrostatic medium (50% ethanol) that had been cooled to 5° C. and itwas pressurized to 50 MPa 2 minutes later, when the temperature in thecenter of the sample had reached 23.5° C. Further changes in temperaturein the center of the sample were monitored with a sensor whilepressurization was continued for 15 minutes. The cooling curve of thesample at this time is shown in FIG. 8. When the cooling curve in FIG. 8is compared with that treated at normal pressure (sample No. 33) andthat pressurized at 50 MPa (sample No. 24) shown in FIG. 5, temperatureof the sample rose to the crystallization starting temperature (33° C.)at 50 MPa immediately after pressurization by the pressurization methodof the present example, indicating that crystallization occurs all atonce. Moreover, because an inflection point is seen at approximately 13minutes, it is concluded with respect to the crystallization completiontime that crystallization is efficiently completed with the standardpressurization time.

By means of the present invention, it has been possible to dramaticallyimprove the crystallization speed and thereby preventpost-crystallization, which was impossible in the past, by addingpressurization simultaneous with cooling to crystallize the fat and oilcomposition, which by conventional methods is accomplished by coolingonly. As a result, improvement of quality of the fat and oil processedfood and marked improvement in efficiency of the production process interms of both time and energy can be expected. Thus, the presentinvention is a long awaited, very effective as means for solving thevarious problems of fat and oil processed foods and is particularlyvaluable for producing fat and oil processed foods.

What is claimed is:
 1. A method of producing a fat and oil compositioncomprising the steps of: melting a fat and oil or emulsion comprisingfat and oil and crystallizing said fat and oil by cooling under force bya cooling means to produce a fat and oil composition in paste form orplastic form, with said melted fat and oil or emulsion comprising fatand oil being pressurized within a range of 10 to 150 MPa under forceduring said cooling.
 2. A method of producing a fat and oil compositionaccording to claim 1, wherein pressurization is performed simultaneouslywith said cooling.
 3. A method of producing a fat and oil compositionaccording to claim 1, wherein pre-cooling said fat and oil or emulsioncomprising fat and oil is performed to such an extent that crystals ofthe fat and oil do not precipitate, then pressurization is started withcontinued cooling.
 4. A method of producing a fat and oil compositionaccording to any of claims 1 through 3, wherein the pressurizationpressure is within a range of 10 to 100 MPa.
 5. A method of producing afat and oil composition according to any of claims 1 through 3, whereinpressurization time is within a range of 1 to 60 minutes.
 6. A method ofproducing a fat and oil composition according to any of claims 1 through3, wherein kneading is performed during said crystallization.
 7. Amethod of producing a fat and oil composition according to any of claims1 through 3, wherein kneading is performed after said crystallization.8. A method of producing a fat and oil composition according to any ofclaims 1 through 3, wherein said emulsion is a W/O emulsion.
 9. A methodof producing a fat and oil composition in any of claims 1 through 3,wherein said fat and oil is an edible fat and oil.